The family of materials known as zeolites constitute a large group of silicates having appreciable void volume within their structures. In the ideal state they may be viewed as built from corner shared SiO.sub.4.sup.4 -tetrahedral building units which form a large range of architectures comprising cavities, channels and cages. In the pure silica forms the structures are charge neutral frameworks stuffed with either neutral molecules, usually water or other neutral solvent molecules, or salt pairs, such as NaCl. These pure silica forms have been designated "clathrasils" or "zeosils" (Liebau et al., Zeolites, v. 6, 373, 1986). More commonly Al substitutes for some of the silica, in which case the framework possesses a net negative charge which is balanced by "exchangeable" cations--commonly those of Groups 1 and 2 of the Periodic Table (Kirk-Othmer Encyclopedia of Chemical Technol., J. Wiley (New York), v. 8, 94, 1965). However, numerous substitutions are now recognized as being possible both in the Si framework substituents and the exchangeable cations, as demonstrated in much of the recent art. A major expansion of these structural types has been achieved with the recognition that AIPO.sub.4 has many structures beyond the well known silica analogues of quartz-tridymite -cristobalite (Flanigen et al., Proc. 7th Intl. Zeolite Conf., Ed. Murakami et al., Kodansha/Elsevier (Tokyo), p. 103, 1985). Many zeolites occur as minerals (Tschernich, "Minerals of the World", Geoscience Press (Phoenix, Ariz.) 1992), some of which have no synthetic counterparts. Similarly many synthetic zeolites have no naturally occurring counterparts. The large number of existing known structures has been reviewed by Meier and Olsen (Atlas of Zeolite Structures", Butterworths-Heinemann Press (London), 1992). The unique catalytic, sorption and ion-exchange properties of these zeolite "molecular sieves" have been utilized in many industrial and environmental processes, and numerous consumer products. (As reviewed in the periodic Proceedings of the International Zeolite Conferences).
There are a large number of synthetic methods for producing zeolites, well illustrated in the patent literature and well reviewed by Barrer (in "Hydrothermal Chemistry of Zeolites", Academic Press (London), 1982), Breck (in "Molecular Sieve Zeolites", J. Wiley (New York), 1974) and Jacobs and Martens (in "Synthesis of High Silica Aluminosilicate Zeolites.", Elsevier (Amsterdam), 1987). Reactants may be general or specific and typical reaction conditions are below about 250.degree. C. and 50 bars pressure. The primary solvent is usually water, but others, such as ammonia (e.g., U.S. Pat. No. 4,717,560) and organic liquids (e.g., U.S. Pat. No. 5,160,500), have also been used. Methods for controlling the zeolite type produced, and its composition, include "seeds" as nucleation centers and organic molecules (frequently alkylammonium salts) as structural "templates". The use of alkylammonium salts as templates, or reaction modifiers, in the preparation of crystalline aluminosilicate zeolite, first discovered by Barrer and Denny (J. Chem. Soc, p. 971, 1961) has led to the discovery of a number of zeolites having no natural counterparts. Breck (ibid, pp. 348-378) and Barrer (Zeolites, v. 1, p. 136, 1981) have reviewed the many aluminosilicate zeolites made using templates; Flanigen, et al., (Proc. 7th. Intl. Zeolite Conf., Kodansha/Elsevier (Tokyo), p. 103, 1986) has reviewed the same for the aluminophosphate family. Possible mechanisms of template structure direction have been discussed by Lok et al., (Zeolites, v. 2, 282, 1982) and Vaughan (in Stud. Surf. Sci. Catal., v. 65, 275, 1991).
The substitution of gallium into known zeolite structures is well known and extensively demonstrated (Selbin and Mason, J. Inorg. Nucl. Chem., v. 20, p. 222, 1961; Melchior et al., Amer. Chem. Soc. Symp. Ser., v. 218, p. 231-48, (1983); Newsam and Vaughan, Proc. 7th. Intl. Zeolite Conf., Kodansha/Elsevier (Tokyo), p. 457, 1986). However, non-mineral hydrated gallium silicates are rare. Exceptions are a recent novel structure designated ECR-9 (U.S. Pat. No. 5,096,686) and another new phase we have designated ECR-14. The latter has the unique X-Ray diffraction pattern shown in Table 1, and occurs as an equilibrium replacement phase in the synthesis of ECR-9, particularly at higher temperatures and long crystallization times.
TABLE 1 ______________________________________ 2theta d(.ANG.) Relative Intensity ______________________________________ 13.36 6.6241 13 16.91 5.2377 25 18.61 4.7633 5 20.69 4.2889 100 20.97 4.2319 34 21.43 4.1423 14 21.91 4.0528 87 23.41 3.7963 44 23.81 3.7332 32 24.69 3.6022 52 26.89 3.3123 63 27.95 3.1893 8 28.41 3.1386 12 29.69 3.0061 39 29.93 2.9824 61 32.33 2.7664 20 32.63 2.7418 9 34.11 2.6260 51 34.73 2.5806 26 36.95 2.4305 23 37.17 2.4166 10 37.67 2.3856 10 37.91 2.3712 7 38.17 2.3556 7 40.35 2.2332 5 40.53 2.2236 6 40.79 2.2101 7 41.67 2.1654 9 42.05 2.1468 8 42.65 2.1179 6 46.98 1.9326 5 47.39 1.9166 8 48.71 1.8677 13 50.41 1.8086 6 50.69 1.7993 6 51.77 1.7642 7 54.59 1.6796 11 57.15 1.6103 11 57.83 1.5930 11 58.83 1.5683 5 ______________________________________
Both ECR-9 and -14 may have structural building units in-common with ECR-34, indicated by a common unit cell c parameter, shown in Table 2:
TABLE 2 ______________________________________ Zeolite Symmetry a.ANG. b.ANG. c.ANG. ______________________________________ ECR-9 orthorhombic 14.2 16.2 8.6 ECR-14 orthorhombic 9.2 9.5 8.6 ECR-34 hexagonal 21.0 -- 8.6 ______________________________________